package leetcode.year2021.month11;

/*
*   200. 岛屿数量
 * */

public class _01_2NumIslands200 {
  public int numIslands(char[][] grid) {
    int ans = 0;

    for (int i = 0; i < grid.length; i++) {
      for (int j = 0; j < grid[0].length; j++) {
        if (grid[i][j] == '1'){
          ans++;
          updateCurrLand(grid,i,j);
        }
      }
    }
    return ans;
  }

  private void updateCurrLand(char[][] grid, int x, int y) {
    int[] h = new int[]{0,-1,0,1};
    int[] l = new int[]{1,0,-1,0};
    grid[x][y] = '0';

    for (int i = 0; i < 4; i++) {
      if (x+h[i] >= grid.length || x+h[i] < 0 || y+l[i] >= grid[0].length || y+l[i] < 0 || grid[x+h[i]][y+l[i]] == 0){
        continue;
      }
      updateCurrLand(grid, x+h[i],y+l[i]);
    }
  }

  /**
   * 200. 岛屿数量
   * 给你一个由 '1'（陆地）和 '0'（水）组成的的二维网格，请你计算网格中岛屿的数量。
   *
   * 岛屿总是被水包围，并且每座岛屿只能由水平方向和/或竖直方向上相邻的陆地连接形成。
   *
   * 此外，你可以假设该网格的四条边均被水包围。
   *
   *
   *
   * 示例 1：
   *
   * 输入：grid = [
   *   ["1","1","1","1","0"],
   *   ["1","1","0","1","0"],
   *   ["1","1","0","0","0"],
   *   ["0","0","0","0","0"]
   * ]
   * 输出：1
   * 示例 2：
   *
   * 输入：grid = [
   *   ["1","1","0","0","0"],
   *   ["1","1","0","0","0"],
   *   ["0","0","1","0","0"],
   *   ["0","0","0","1","1"]
   * ]
   * 输出：3
   *
   *
   * 提示：
   *
   * m == grid.length
   * n == grid[i].length
   * 1 <= m, n <= 300
   * grid[i][j] 的值为 '0' 或 '1'
   */
}
